Depression is a complex disease with treatment options that help one group of patients but are ineffective for another. There are many reasons why your depression may not have the same clinical factors as someone else’s, and one of the most discussed factors is genetics. There are numerous cases where a patient suffering from depression has had a parent and/or close relative who had also suffered from the disease and for many years this was considered an unfortunate coincidence.
Depression research has come a long way since those days of ‘unfortunate coincidences’; diagnosis now takes into account the genetic predisposition of developing depression symptoms as well as the risks of becoming depressed. For children of a depressed parent, the risk of depression is much higher. Some research reports that 50% of these children will have an episode of major depression by the age of 20. Another study indicates that inheriting major depression is higher in women than in men. In addition to inheriting depression, having depressed parents can lead to negative consequences for children ranging from poor school performance to higher visits to emergency rooms.
Risk is not the same as a genetic predisposition. One could be genetically predisposed which would put a person at a higher risk for depression, but this statement doesn’t necessarily work the other way around. Studies have been trying to identify specific genetic markers that could be inherited that put an individual at a higher risk for depression, but up until recently this theory was inconclusive. In 2011, a study of 800 families with recurrent depression was able to find a DNA region linked to depression. Meanwhile a separate and unrelated study was able to replicate the findings. These studies identified a genetic variation in a region called chromosome 3p25-26 However more than one gene is believed to be involved when looking at hereditary depression.
Scientists think around 40% of the risk of developing depression is contributed by genes, with the rest linked to environmental factors such as family dysfunction, socio-economic environment, abuse, and others. The discussion regarding the link between risks and genetics is still to be resolved, but it is safe to say that depression is not related to a single phenomenon, which makes it difficult to figure out the exact cause.
Doctors believe that an altered brain structure and chemical function causes depression when chemicals called neurotransmitters become imbalanced. The stress of a traumatic event such as losing a loved one, the loss of a job, medications, alcohol or substance abuse, hormonal changes, or even the season may lead to chemical imbalance.